More than a century after a catastrophic disaster wiped out most of humanity and covered much of Earth with ice, 15-year-old Cass yields to the voice in her head urging her to embark on a dangerous journey across a poisoned sea to the mythical land, Blue.

More than a century after a catastrophic disaster wiped out most of humanity and covered much of Earth with ice, 15-year-old Cass yields to the voice in her head urging her to embark on a dangerous journey across a poisoned sea to the mythical land, Blue.